Plant or animal growing devices, such as greenhouses, and artificial water ponds for growing fish and cattle farms, are in use all over the world. In such devices, energy in the form of heat is used by several heat users, such as a heating unit, that serves to provide an adequate temperature of the medium in which the specific type of plant or animal grows (typically air or water). The heat source may obtain its energy in any manner, typically by burning fossil fuel or by catching solar power. The heat users may vary according to the geographical circumstances, such as the availability of fresh water or seawater. For example, one of the heat users may be a thermal desalination unit, in locations where seawater is abundant and fresh water is scarce.
European Patent No. EP 1 071 317 describes a greenhouse and a heat source for producing steam comprising at least one collector situated above rotatable mirrors which can follow the movement of the sun according to the seasons and can make the top-side of the greenhouse practically light-tight. The water, in the form of steam, produced in the collector is distributed to two heat users, in a ratio determined by valves, and flows, after condensation, back to the heat source. The two heat users are (1) a thermal desalination unit and (2) a steam turbine, for producing electricity. The produced desalinated water is used for growing plants in the greenhouse. Part of the solar radiation enters the inner space of the greenhouse, where it is used for photosynthesis of plants.